Adding a 242 option

Last Updated : Jul 06, 2021 |
Prolog information
Metadata
Keywords:
In addition to issuing IP address information, DHCP servers can issue other information in response to requests for different specific DHCP option numbers. The settings for each option are attached to the scope. 1600 and 9600 Series H.323 IP phones use SSON 242 to request additional information from a DHCP server. The option should include defining the address of the phone's H.323 gatekeeper (the IP Office) and the address of the HTTP file server.
  1. Right-click on the DHCP server.
  2. From the pop-up menu, select Predefined options.
  3. Select Add.
  4. Enter the following information:
    1. In Name enter 16xxOptions.
    2. In Data type enter String.
    3. In Code enter 242.
    4. In Description enter IP Phone settings.
  5. Click OK.
  6. In the string value field, enter MCIPADD=xxx.xxx.xxx.xxx,MCPORT=1719,HTTPSRVR=yyy.yyy.yyy.yyy,HTTPDIR=z, VLANTEST=0.
    ADDITIONAL INFORMATION:
    • The maximum string length is 127 characters. To reduce the length, the TFTP Server address can be specified through attaching an Option 66 entry to the Scope. See Alternate Options.
      MCIPADD= is the H.323 Gatekeeper (Callserver) address. Normally, this is the IP Office Unit's LAN1 address. You can enter several IP addresses, separating each by a comma with no space. This allows specification of a fallback H.323 gatekeeper. The phones will wait three (3) minutes before switching to the fallback and will not switch back when the first server recovers, until the phone is rebooted.
    • MCPORT= the RAS port address for initiating phone registration. The default is 1719.
    • HTTPSRVR= the HTTP file server IP address.
    • HTTPDIR= the HTTP file directory where the IP phone files are located. This entry is not required if those files are in the server's root directory.
  7. Click OK
  8. Expand the server by clicking on the [+] next to it.
  9. Click on the scope you just created for the 1600 and 9600 phones.
  10. In the right-hand panel, right-click on the scope and select Scope Options.
  11. In the general tab, make sure 242 is checked.
  12. Verify the String value is correct and click OK.
Next steps
Having created a 242 option and associated with the scope we want used by the IP phones, we now need to activate the scope
Related links
Alternate DHCP Server Setup